"In this respect, there is a connection between the occurrence of the phenomenon and the strong levels of immigration in 2015," Münch said, adding that there was no evidence the attacks had been somehow organized.

Cologne was the city where the majority of women were sexually abused - some 650, followed by Hamburg where over 400 women suffered, a police report said.

In April, the latest report by the local branch of the German Interior Ministry said that almost all the suspects involved in the Cologne New Year attacks were from outside Germany, and two-thirds of them came from Morocco or Algeria.

In June, two men were found guilty of sexual assault on New Year’s Eve in Cologne and were given probationary sentences. The court said it was evident that one man, named as Hussein A., kissed a young woman against her will. Another man, an Algerian national, was a part of a group that sexually harassed women.

German media reported that two more men were found guilty of sexual assault charges in Düsseldorf and Nürtingen.

An overwhelming 1.1 million asylum seekers came to the country in 2015, and Germans are concerned about the future: 81 percent of the country’s citizens say the migrant crisis is “out of control” under Chancellor Angela Merkel’s authority, according to a February poll.